Biology - Chp 9 - Respiration - PowerPoint

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Biology - Chp 9 - Respiration - PowerPoint

  1. 1. Chapter 9 Cellular Respiration
  2. 2. • Feel the Burn• Do you like to run, bike, or swim? These all are good ways to exercise. When you exercise, your body uses oxygen to get energy from glucose, a six-carbon sugar.1. How does your body feel at the start of exercise, such as a long, slow run? How do you feel 1 minute into the run; 10 minutes into the run?2. What do you think is happening in your cells to cause the changes in how you feel?3. Think about running as fast as you can for 100 meters. Could you keep up this pace for a much longer distance? Explain your answer.
  3. 3. 9-1 Chemical Pathways• Food provides living things with the chemical building blocks they need to grow and reproduce• Food serves as a source of raw materials used to synthesize new molecules• Food serves as a source of energy
  4. 4. calorie• The amount of energy needed to raise the temperature of 1 gram of water 1 Celsius degree
  5. 5. Calorie• 1000 calories
  6. 6. Chemical PathwaysGlucose Glycolysis Krebs Electron cycle transport Fermentation Alcohol or (without oxygen) lactic acid
  7. 7. Glycolysis• First step in releasing energy from glucose
  8. 8. Cellular Respiration• The process that releases energy by breaking down food molecules in the presence of oxygen
  9. 9. The equation for cellular respiration is…O2 + C6H12O6 CO2 + H2O + ATPOxygen Glucose Carbon Water Energy dioxide
  10. 10. Glycolysis• The process in which one molecule of glucose is broken in half producing two molecules of pyruvic acid 2 Pyruvic acid Glucose To the electron transport chain
  11. 11. ATP Production• You need to put a little energy in to get going• 2 molecules of ATP are used up to get glycolysis going• 4 molecules of ATP are produced at the end of glycolysis• Net gain of 2 ATP molecules
  12. 12. NADH Production• One of the reactions of glycolysis removes 4 high energy electrons and passes them to a carrier called NAD+• NAD+ accepts a pair of high energy electrons and becomes NADH• NADH holds the electrons until they can be transferred to other molecules
  13. 13. NADH Production• Energy yield from glycolysis is small, but the process is fast• Doesn’t require oxygen
  14. 14. Problems with glycolysis• NAD+ molecules fill up with electrons quickly• Without NAD+ the cell cannot keep glycolysis going and ATP production stops
  15. 15. Chemical PathwaysGlucose Glycolysis Krebs Electron cycle transport Fermentation Alcohol or (without oxygen) lactic acid
  16. 16. Fermentation• Releases energy from food in the absence of oxygen
  17. 17. Fermentation• During fermentation, cells convert NADH to NAD+ by passing high energy electrons back to pyruvic acid• Changes NADH back to NAD+• Allows glycolysis to keep producing ATP
  18. 18. Anerobic• Does not require oxygen
  19. 19. There are 2 main types of fermentation1. Alcoholic Fermentation2. Lactic Acid Fermentation
  20. 20. Alcoholic Fermentation• Carried out by yeastPyruvic Acid + NADH alcohol + CO2 NAD+
  21. 21. FermentationYeast
  22. 22. Lactic Acid Fermentation• Regenerates NAD+ so that glycolysis can continuePyruvic Acid + NADH lactic acid + NAD+ Glucose Pyruvic acid
  23. 23. Lactic Acid Fermentation• Lactic acid is produced during rapid exercise when the body is low on O2• You quickly run out of O2• The buildup of lactic acid causes painful burning sensation (This is why you feel sore)
  24. 24. Lactic acid makes you sore • Your body creates an oxygen debt • You must repay that debt with heavy breathing after the exercise
  25. 25. Good Lactic Acid• Unicellular organisms that produce lactic acid during fermentation are used to make• Cheese• Yogurt• Buttermilk• Sour cream• Pickles• Sauerkraut• Kimchi
  26. 26. Do Now• Answer the questions on pg 6 of your Chapter 5 packet.
  27. 27. 9-2 The Krebs Cycle and Electron Transport• At the end of glycolysis, about 90% of the chemical energy that was available in glucose is still unused, locked in high energy electrons of pyruvic acid• To export the rest of that energy, the cell turns to the worlds most powerful electron acceptor… Oxygen
  28. 28. Aerobic• Requires oxygen
  29. 29. • RESPIRATION • CELLULAR RESPIRATION• Breathing • Energy releasing pathways
  30. 30. Glucose Glycolysis Krebs Electron cycle transport Fermentation Alcohol or (without oxygen) lactic acid
  31. 31. The Krebs Cycle• Pyruvic Acid is broken down into carbon dioxide in a series of energy – extracting reaction
  32. 32. The Krebs Cycle• CO2 released is the source of all CO2 in your breath• Makes ATP• High energy electron carriers are used to make huge amounts of ATP
  33. 33. Glucose Glycolysis Krebs Electron cycle transport Fermentation Alcohol or (without oxygen) lactic acid
  34. 34. Electron Transport• Uses the high – energy electrons from the Krebs cycle to convert ADP into ATP
  35. 35. A: Electron Transport• High – energy electrons from NADH and FADH2 are passed along the electron transport chain• At the end of the electron transport chain is an enzyme that combines these electrons with hydrogen ions and oxygen to form water• _____Oxygen_____serves as the final electron acceptor of the electron transport chain
  36. 36. B: Hydrogen Ion Movement• Every time 2 high-energy electrons transport down the electron transport chain, their energy is used to transport hydrogen ions (H+) across the membrane.• During electron transport, H+ ions build up in the intermembrane space, making it positively charged.• The other side of the membrane, from which those H+ ions have been taken, is now negatively charged.
  37. 37. C: ATP Production• The inner membranes of the mitochondria contain protein spheres called ATP synthases.• As H+ ions escape through channels into these proteins, the ATP synthases spin. Each time it rotates, the enzyme grabs a low-energy ADP and attaches a phosphate, forming high-energy ATP.• On average, each pair of high-energy electrons that moves down the electron transport chain provides enough energy to convert 3 ADP molecules into 3 ATP molecules.
  38. 38. Cellular Respiration ATPGlucose +(C6H1206) Carbon Electron Krebs Dioxide + Glycolysis Transport Cycle (CO2)Oxygen Chain (02) + Water (H2O)
  39. 39. The Totals • 18 times as much ATP can be generated from glucose in the presence of oxygen • The final wastes of cellular respiration are – CO2 – H2O • Q: How efficient is this? • A: 38 percent of the total energy of glucose is released. – More efficient at using food than car engines are at burning gasoline • Q: What happens to the rest of the energy? • A: Given off as heat
  40. 40. Comparing Photosynthesis and Cellular Respiration• They are almost the opposite processes• Savings account analogy – Photosynthesis – “deposits energy” – Respiration – “withdraws energy”• Photosynthesis removes CO2, cellular respiration puts it back• Photosynthesis releases O2, cellular respiration uses O2 to release energy

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